WHY Can’t I *Can* that?

*** Note From The APN ***

This topic often becomes controversial.  There seem to be many differing opinions out there regarding canning different types of food.  The bottom line is this:  When you can food you must make a choice whether you want to follow “age-old” advice or scientific data concerning safe heat levels food must reach in order to kill the lingering bugs and germs that are omni-present in today’s store bought food.  

This article presents well researched and heavily documented information regarding the baseline for how to can SAFELY.  None of what is presented is opinion other than the opinion that when you are preserving food for your family to eat, it is best to err on the side of absolute safety.  

Comments on this article which are derogatory, attack the author or attack those of us who consider family food safety to be paramount will be deleted.  If commenting on this article becomes a persistent issue, comments will be turned off.  

But I read about it online!

Getting your canning instructions and procedures from a random site on the internet (even ours) without referring to carefully tested and established guidelines, can be extremely dangerous and even deadly. The ingredients used in foods today are not the same as they were 100 years ago. Likewise, the contaminants and germs that store-bought food is exposed to is not the same it was 100 years ago. Due to advances in the fields of microbiology, we are now better able to test foods for dangers than we were 100 years ago. Due to this, canning guidelines have changed.


Where to can get Accurate, Safe, Time Tested, Food Storage Information:

When I make food to put into storage I rely both on time proven methods and the science behind them. I will talk to real people who are more experienced than I – like my grandma, mother and aunts. Master Preservers and Food Specialists are also a great resource for a question or new recipes and can be reached through your local county extension office, or found by clicking here. Most importantly, I also use trusted canning books like the Ball Blue Book as a reference and the National Center for Home Food Preservation (USDA home preservation recommendations, recipes, and guidelines) to validate those methods. While I don’t think those recommendations are “the law of the land” most of them do have a very good scientific reasons behind them. Every time I have read a recommendation that I disagree with and proceeded to research it myself I have discovered that they do in-fact, have good reasons behind them.

But I don’t trust the USDA.

Many people assume that USDA canning recommendations are in existence to keep people (like preppers) from storing their own food – in order to keep them dependent on the system. While this line of thinking sells a lot of books, it is flawed as most of those “guidelines and recommendations” (and yes, even the USDA admits they are ONLY guidelines and recommendations) have been around longer than the term “prepper’ has and even longer than the first formal survivalist movements.

They exist because at one time our government did actually encourage people to can, garden, and make their own food to take the pressure off the ‘system’ so that more food and supplies could be sent to the war effort. This was also done so that ‘rationing’ wouldn’t hurt the average person so much. Since they were encouraging people to can – they also took some responsibility for providing the public with information on how to do it safely. Thus, with some help from the industry (Ball, Kerr, and the manufacturers of pressure canners) the canning “guidelines and recommendations” as we know them today, were born.

While the guidelines are updated continuously, in the grand scheme of things, they have changed very little since then. The changes that have been noticed the most (like the removal of a bacon canning recipe and a pumpkin butter recipe) are due to new information that has come in, from university and industry studies (not necessarily from the government itself, which has been unable to come up with any funding for new home canned goods research for decades). In some cases recipes have been removed because of ‘lack’ of information – since no testing has been done, they can’t verify it as safe and thus it is removed.

In essence the guidelines were developed and centralized to provide people with safe information on how to can homegrown goods. After all the costs of not doing so are steep (read below). They were especially targeted to people new to the practice at the time, and especially those more than one generation removed from the farm and garden, now living in city.

But why?

Now, with that being said – here are the top foods people commonly try to can that should NOT be canned,  not water bathed canned OR pressure canned, and certainly not oven-canned.  Here’s why (stay with me, I will try to explain everything in a down to earth way):


Butter is a dairy product and shouldn’t be canned. Milk and butter are “low acid foods”, this means they can support the outgrowth of C. botulinum and toxin formation in a sealed jar at room temperature. Unique fats in milk and butter (the dairy fats) can protect botulism spores from the heat of even a pressure canner. SO, if you buy butter from the store and there was one person at the dairy where that butter came from, that was not following cleanliness procedures, you could get sick from canning it.Botulism spores (commonly found in dirt) are not killed by the pasteurization process of milk so they can still be in there at any time. While undesired, this usually isn’t a big deal because if ingested they can pass through a healthy adult without causing any harm (or a resulting product recall). However, if you take that same dairy product containing the spores and put in a jar where you seal it off from oxygen for an extended period of time at room temperature…..it can grow undisturbed into one of the many strains of Clostridium botulinum, and produce an extremely lethal neurotoxin until you open it up and eat it.How lethal you may ask?

“Botulinum toxin is the most acutely toxic substances known, with a median lethal dose of about 1 ng/kg when introduced intravenously and 3 ng/kg when inhaled. This means, depending on the method of introduction into the body, a mere 90–270 nanograms of botulinum toxin could be enough to kill an average 90-kg (200-lb) person, and four kg of the toxin, if evenly distributed, would be more than enough to kill the entire human population of the world.…. Botulinum toxin has been recognized and feared as a potential bio terror weapon.”

That lethal. Its odorless, tasteless and can have no visible appearance, and the lid to the jar will still have a nice seal. If ingested immediate medical attention and a dose of anti-toxin is usually required to prevent death and nerve damage. That’s why it’s such a big deal.

Food quality has improved AND medical response time has also improved that’s why you rarely hear of Botulism poisoning cases anymore. If you disregard this information, in a sense, you are trusting the same mega farms that brought you the salmonella egg poisonings and following egg recall in 2010 to bring you perfectly clean milk and butter.

Some people take even more short cuts with butter and water bath can it – or worse, can it in their oven which guarantees that the temperatures won’t get high enough in the jar to kill the spores, increasing their risk. Dry heat from your oven is slow to penetrate into jars and the recommended time is not long enough for the center of the jar to get up to temperature, the only way you can be certain it got up to temp is to break the seal and check which is counter productive to your efforts.

Water boils at 212° F near sea level and because of the heating curve even if you increase the temperature on your stove the water NEVER gets any hotter, so water bathing your butter also will not bring it up to a temperature where Clostridium botulinum can be killed (this is why water bath canning relies more on acidity than heat to sterilize food). Botulism spores are killed after being exposed to temperatures of 240˚ for a specific period of time, through scientific testing those “times” have been determined and are listed as “processing times” with each approved canning recipe.

One way you CAN store butter for the long term is by ‘clarifying’ it first, when you ‘clarify’ butter you remove the dairy fats, making it more healthy and shelf stable – this is also called ghee. Prepared this way you can store butter on the shelf without canning it for over a year.

Milk or Milk Heavy Products like Condensed Soups

I’ve articles claiming that the only reason why it’s not recommended to can milk is solely because of the resulting unfavorable taste and texture of the milk. In truth that is only part of the reason: Dr. Elizabeth L. Andress, National Director of Home Food Preservation, University of Georgia Department of Foods and Nutrition and Dr. Andress, a Professor and Extension Food Safety Specialist have recently commented “the amount of heat that would have to be applied to kill harmful bacteria” would be “extremely detrimental to its quality.” But it’s not just the taste and texture of the milk, Dr. Andress states, “milk is a finely balanced emulsion of proteins in water. If the milk proteins are over-heated, they drop out of suspension and the milk separates” the visible separation is an indication that the same ‘life sustaining’ proteins of the milk are no longer intact defeating the purpose of canning milk. Also, milk is a LOW acid food (see above explanation) and dairy fats can protect botulism spores from the heat of canning. So if your milk somehow does have spores in it and you put it in a jar and seal it off from oxygen for an extended period of time at room temperature…..it can grow into one of the many strains of Clostridium botulinum, and produce an extremely lethal neurotoxin.

Pureed or Mashed Squash and Pumpkin and Pumpkin Butter

In purée form these two should not be canned, not water bathed or pressure canned. However in cubed form it is safe to “pressure” can them. Here is why: Pumpkin is a low acid food (low acid foods can support the outgrowth of C. botulinum) when pumpkin and squash are pureed it’s really thick (dense). Through recent testing several universities have discovered that not even a pressure canner can produce enough heat to reliably penetrate the jar to the center of the purée, it is just too dense. When pumpkin and squash are cubed and suspended in water the pressure canning process is reliable every single time. The reason why canning purée pumpkin or pumpkin butter was recommended by the USDA and now it’s not, is because further testing was done which indicated that sometimes the pressure canning process worked and sometimes its did not, even with the addition of lemon juice the tests were still coming back with positive for Botulism spores. With one minor change to the process (using cubes and not a purée) it was 100% reliable so the recommended recipes for purée pumpkin and squash were withdrawn and replaced by cubed recipes. This change was not made to annoy everyone it was made with our safety in mind.

Rice and Bread (and pastas)

Adding rice, bread, or pastas to canned food recipes, like soups, is also not recommend. Canning rice or bread or cake products straight is also not recommended. It changes the density and increases the pH of the food, this may alter it to the point where you would not get adequate heat penetration to kill off the nasty bugs. There is also the problem with these of ingredients expanding. If you are canning with a jar that is flawed you run the risk of an exploding jar ruining your entire batch. Food manufacturers produce canned soups with these ingredients with high temperature/pressure retort sterilization machines, but we do not have this capability for our home canned goods. Canned cakes and breads are a favored item of the “anything can be canned” crowd. Not only do they meet the botulism criteria of being moist and low acid, the airless center of the cake just doesn’t get hot enough to kill botulism that could get there a number of ways. It doesn’t matter if the oven temperature is at 350 degrees; the internal temperature will not get anywhere near required 240 degrees for 30 minutes that is required for it to be safe. Since rice, wheat, and cake mix store so easily dry – I recommend dry canning them (click here to read an article) for separate storage. Can make soups without rice and noodles – and simply add them later when you go to use the can of soap.


It is not recommended to can eggs at all. I know people who would fight me on this until their death, because, they claim they have found ways to make it ‘safer’ but here are the facts. Eggs are a low acid and a high density food. Hard boiled eggs have a pH around 6.8, so it is possible for botulism to grow because the vinegar does not penetrate deeply into the egg. You can, however, pickle eggs then refrigerate them and they will then last an unnervingly long time this way. There are no safe tested recipes for canning hard-boiled eggs, pickled or otherwise. Food manufacturers get away with canning eggs because their capabilities are greater than what our home pressure canners can do – this isn’t a conspiracy it’s just a fact of life. If you are wondering why pickled eggs can sit at a saloon out of the fridge and be safe, the answer is because saloon patrons usually eat the eggs within a couple of days. When eggs are pickled, if some nasty bug survives in the middle of the egg away from the vinegar it will grow undisturbed at room temperature until the egg is eaten, the longer it sits at room temperature the more it grows. That is why it’s wise to refrigerate all pickled eggs. Now if you want to do your own research and part ways with the safety guides here that is up to you. Knowing what I know now about the science behind canning – I am sticking with the safety guides on this one.


Chili can be canned as opposed to the products above, but most chili recipes are only supposed to canned in pints jars, as in this recommended recipe here so you have pay attention to the recommended jar size and corresponding processing time. This is because chili is a low acid food, it is also very dense. If you put it in a quart jar as opposed a pint jar the contents of the jar may be too dense for the temperature in the middle of the jar to consistently reach 240°F for 30 minutes, in another words it could stray beyond our home pressure canner capabilities.You also should not change the recommended chili recipe to fit your families favorite recipe or to create a “survival chili” recipe. I know this seems like a drag, but all the research that has been done on chili has been done on those specific recipes for chili – those acid levels, those density levels and ingredients, not on your families favorite chili recipe. For those quart jar fans out there I did find a recipe for chili in the 2011 Ball Blue Book that included a recommendation for processes quart jars. I trust that Ball (Jarden Home Brands) would not include an unproven recipe in their book – so you can reference the Blue Book for that.

What “Research-Based” home canning means

“The development of a canning recipe is an extensive process.  It involves repeating the entire preparation and canning process 15-30 times to obtain accurate heat penetration data.  Then, microorganisms are purposefully put into the jars before processing to make sure the processing time is sufficient to destroy them. This research must take place in a laboratory with equipment for testing heat penetration and microbiology. This is why processing times cannot be made up!  It’s also why a sealed jar does not mean it’s a safe jar,” (Lizann Powers-Hammond and Val Hillers WSU Consumer Food Safety).So while that doesn’t mean your families recipe is unsafe, it does mean that you will most likely never know for sure.

But I have been canning that for years and no one has gotten sick.

Many people say it must be safe to can because after all, they’re alive, aren’t they? I can’t even count how many times I have heard or read someone saying, “I have been canning and eating ______ for years and never had a problem.” That’s like saying “I’ve been driving my car for 10 years without a seat belt and have never gotten in an accident,” the day before you are thrown through your windshield on your way home.

Past performance does not guarantee future results.

A good rule of thumb is if there are no recipes available in trusted canning guides, then either no tests have been done, or it has been tested and found unsafe.  I know it is frustrating to not be able to preserve something that you like inexpensively, but sometimes it is just safer to go buy the powdered, freeze-dried or industrial shelf stable version to store.

I don’t want to scare anyone into not canning, home canning food is basically safe, as long as you follow the scientifically tested recipes and procedures.  When you deviate from those methods and directions you put yourself and whomever you feed at risk, how much risk is up to you.

So instead of blindly trying out random recipes that you read on people online – cross-check the recipes you find with the  Ball Blue Book, or The Complete Guide to Home Canning (the USDA guide) to see what similar recipes recommend for processing times.  If you can’t find a recipe, there MAY BE A GOOD REASON for that.  If you still have questions about using the recipe consult your local extension office. My sources for this article (at the time it was posted) are linked to each individual explanation and/or above in blue.

TIP: Proper refrigeration of foods at temperatures below 3°C (38°F) retards the growth of Clostridium botulinum and most other bacteria. The organism is also susceptible to high salt, high oxygen, and low pH levels (acidity). The lethal toxin produced by the bacteria is rapidly destroyed by heat, such as in thorough cooking, but you need to bring it up to boiling temperatures.

Note From the Author concerning the Content of this Article:

I feel we (as preppers) are all on the same team working towards a common goal.  I wrote this because someone on the internet NEEDED to be very clear about safe canning practices.  I presented this information just as everyone else who posts canning articles presents their information, and I have left it up to you, the readers, to make up your own minds.  I feel you need all of the information available to do that – not just the feel good stuff.  At no point do I claim to be an expert in this article which is why I thoroughly cited all of the information and provided links where you could locate and get in touch with canning and food experts.

*On a final note – I want to make it perfectly clear, that I have nothing against commercial farms or dairies, or their quality control standards. As they are strict and double and triple checked, but, humans error.  They also fill a need.   All the small farms in the US together would not be able to feed the American people alone it is not mathematically possible.  Demonizing mega farms will never achieve the goals of a safer, healthier food supply.  It is a problem that can only be solved by the consumer, not the government. 


This is an archive of: http://americanpreppersnetwork.com/2012/11/why-cant-i-can-that.html